View source for S-4 Regulations of the IHO for international (INT) charts and chart specifications of the IHO

== Overview == 
{| class="wikitable"
| Full name
|S-4, Regulations of the IHO for international (INT) charts and chart specifications of the IHO
|-
| Version
| Edition 4.4.0
|-
| Amendments
| None
|-
| Corrigenda
| None
|-
| Published by
| IHO
|-
| Languages
| English, French
|-
| Online overview
| http://iho.int/iho_pubs/standard/S-4/S-4_e4.4.0_EN_Sep13.pdf
|-
| Type of standard
| IHO Regulations <br/>Application level
|-
| Related standard(s)
| S-11 Guidance for the preparation and maintenance of international chart schemes and catalogue of international charts <br/>S-57 IHO transfer standard for digital hydrographic data <br/>S-52 Specifications for chart content and display aspects of ECDIS <br/>S-65 ENCs: Production, maintenance and distribution guidance
|-
| Application
| S-4 specifies regulations of the IHO for International (INT) charts and chart specifications of the IHO. It specifically looks at regulations of the IHO for International (INT) charts, chart specifications of the IHO for medium- and large-scale National and International (INT) charts, and chart specifications of the IHO for small-scale International (INT) charts.
|-
| Conformance classes
| None specified
|}

== Scope == 
The publication S-4 (previously M-4) ‘Regulations of the IHO for International (INT) Charts and Chart Specifications of the IHO’, includes:
:* Part A: ‘Regulations of the IHO for International (INT) Charts’
:* Part B: ‘Chart Specifications of the IHO for Medium- and Large-scale National and International (INT) Charts’
:* Part C: ‘Chart Specifications of the IHO for Small-Scale International (INT) Charts’

The three parts of S-4 are further subdivided into Sections dealing with specific topics. Regulations and Specifications relating to particular topics may be found either by their subject matter in the Contents page at the beginning of each Section, or by reference to column 5 of INT 1 for Part B and the index for Part C. Cross referencing draws attention to related Regulations, Technical Resolutions and Specifications. This publication was developed and maintained by the IHO’s Chart Standardization Committee to 2003. Its maintenance is now the responsibility of the Chart Standardization and Paper Chart Working Group, to which comments and corrections should be advised.

== Implementation benefits == 
The regulations set out in S-4 are very detailed and provide guidelines for every aspect of a chart from design through production to dissemination. It is important that charts are designed and produced according to these regulations and guidelines to ensure safety for navigation. The intended users need to be able to read and understand charts produced by any country at any scale; this can only be ensured through rigorous regulations.

== Implementation guidelines == 
When S-4 was originally prepared, the term chart referred to a paper chart. Since then, electronic charts have become widely used. Digital charts require additional regulations, which are set out in S-52, S-57 and S-61. S-4 provides regulations for three types of charts:

:# International Charts<br/>There are two types of international charts: marine navigation and information source. Marine navigation charts are produced by national hydrographical offices to cover international waters. The main aim of these charts is to assist in the safe navigation of coastal waters. Information sources are large-scale chart publications showing the detailed configuration of the seabed offshore. The information about the seabed shape is required by various users, for example, for navigation and construction purposes.
:# Medium- and Large-scale Charts <br/>Medium- and large-scale charts are charts with a scale of 1:2 000 000 and larger.
:# Small-Scale Charts <br/> Small-scale charts are charts with a scale smaller than 1:2 000 000. These charts provide a complete and comprehensive small-scale coverage, usable by all nations, for the world’s oceans.

S-4 specifies regulations for the following aspects of international charts: general, schemas of International charts, specifications for International charts, maintenance of international charts, exchange of reproduction material, and financial aspects.

For medium- and large-scale charts the regulations are more detailed. The regulations cover topics such as the terms and conventions used, translations of terms, symbology, geographic units, text styles, and use of colour.

Lastly, the regulations for small scale charts look at the chart in general, the format of the chart, topography, hydrography and aids to navigation, geographic names, and style sheets.